Ah I see...

First you must save the User MIDI settings in the keyboard! After that you can save them to SD Card.

Set up your keyboard as you like it.
Go to Program Menus > MIDI > MIDI Presets.
Go to Page 4. Here you can save 3 MIDI presets, including the split point.
(Page 3 is for recalling the presets)

Now you can save to SD Card in the .md file.

I hope this helps.